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result(s) for
"Ohta, D"
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Isolation of a cDNA and a Genomic Clone Encoding Cinnamate 4-Hydroxylase from Arabidopsis and Its Expression Manner in Planta
by
Sato, Ryo
,
Daisaku Ohta
,
Masaharu Mizutani
in
Alfalfa
,
Amino Acid Sequence
,
amino acid sequences
1997
We have isolated a cDNA for a cytochrome P450, cinnamate 4-hydroxylase (C4H), of Arabidopsis thaliana using a C4H cDNA from mung bean as a hybridization probe. The deduced amino acid sequence is 84.7% identical to that of mung bean C4H and therefore was designated CYP73A5. The CYP73A5 protein was expressed in insect cells using the baculovirus expression system and when reconstituted with lipid and NADPH-cytochrome P450 reductase resulted in C4H activity with a specific activity of 68 nmol min-1
$\\text{nmol}^{-1}$ P450. Southern blot analysis revealed that CYP73A5 is a single-copy gene in Arabidopsis. C4H (CYP73A5) expression was apparently coordinated in Arabidopsis with both PAL1 and 4CL in response to light and wounding. Although the light induction of CHS followed a time course similar to that observed with C4H, no induction of CHS was detected upon wounding. On the other hand, the C4H expression patterns exhibited no significant coordination with those of PAL2 and PAL3. A C4H promoter region of 907 bp contained all of the three cis-acting elements (boxes P, A, and L) conserved among the PAL and 4CL genes so far reported as controlling expression.
Journal Article
Arabidopsis CYP707As Encode (+)-Abscisic Acid 8′-Hydroxylase, a Key Enzyme in the Oxidative Catabolism of Abscisic Acid
by
Shigeki Saito
,
Daisaku Ohta
,
Ohigashi, Hajime
in
abscisic acid
,
Abscisic Acid - metabolism
,
Abscisic Acid - pharmacology
2004
Abscisic acid (ABA) is involved in a number of critical processes in normal growth and development as well as in adaptive responses to environmental stresses. For correct and accurate actions, a physiologically active ABA level is controlled through fine-tuning of de novo biosynthesis and catabolism. The hydroxylation at the 8′-position of ABA is known as the key step of ABA catabolism, and this reaction is catalyzed by ABA 8′-hydroxylase, a cytochrome P450. Here, we demonstrate CYP707As as the P450 responsible for the 8′-hydroxylation of (+)-ABA. First, all four CYP707A cDNAs were cloned from Arabidopsis and used for the production of the recombinant proteins in insect cells using a baculovirus system. The insect cells expressing CYP707A3 efficiently metabolized (+)-ABA to yield phaseic acid, the isomerized form of 8′-hydroxy-ABA. The microsomes from the insect cells exhibited very strong activity of 8′-hydroxylation of (+)-ABA (Km = 1.3 μM and kcat = 15 min-1). The solubilized CYP707A3 protein bound (+)-ABA with the binding constant $K_{\\text{s}}$ = 3.5 μM, but did not bind (-)-ABA. Detailed analyses of the reaction products confirmed that CYP707A3 does not have the isomerization activity of 8′-hydroxy-ABA to phaseic acid. Further experiments revealed that Arabidopsis CYP707A1 and CYP707A4 also encode ABA 8′-hydroxylase. The transcripts of the CYP707A genes increased in response to salt, osmotic, and dehydration stresses as well as ABA. These results establish that the CYP707A family plays a key role in regulating the ABA level through the 8′-hydroxylation of (+)-ABA.
Journal Article
Fast, self-adaptive timing-synchronisation algorithm for 802.11 MANET
by
Davis, P.
,
Hasegawa, A.
,
Tanaka, H.
in
Applied sciences
,
Equipments and installations
,
Exact sciences and technology
2006
In multihop ad hoc networks that use conventional IEEE 802.11, long transient resynchronisation states are often generated when multiple IBSSs merge. A simple modification of the conventional timing synchronisation method is proposed to reduce such synchronisation bottlenecks. When the proposed modification is applied, a self-adaptive synchronisation ability is observed in simulations, which makes resynchronisation times much shorter and reduces energy consumption.
Journal Article
Molecular Cloning and Characterization of ATP-Phosphoribosyl Transferase from Arabidopsis, a Key Enzyme in the Histidine Biosynthetic Pathway
by
Rosarin Kunpaisal-Hashimoto
,
Silvia Münzer
,
Daisaku Ohta
in
Amino Acid Sequence
,
amino acid sequences
,
Amino acids
2000
We have characterized two isoforms of ATP-phosphoribosyl transferase (ATP-PRT) from Arabidopsis (AtATP-PRT1 [accession no. AB025251] and AtATP-PRT2), catalyzing the first step of the pathway of hisidine (His) biosynthesis. The primary structures deduced from AtATP-PRT1 and AtATP-PRT2 cDNAs share an overall amino acid identity of 74.6% and contain N-terminal chloroplast transit peptide sequences. DNA-blot analyses indicated that the ATP-PRTs in Arabidopsis are encoded by two separate genes with a closely similar gene structural organization. Both gene transcripts were detected throughout development, and protein-blot analysis revealed predominant accumulation of the AtATP-PRT proteins in Arabidopsis leaves. The His auxotrophy of a his1 mutant of Saccharomyces cerevisiae was suppressed by the transformation with AtATP-PRT1 and AtATP-PRT2 cDNAs, indicating that both isoforms are functionally active ATP-PRT enzymes. The Km values for ATP and phosphoribosyl pyrophosphate of the recombinant AtATP-PRT proteins were comparable to those of the native ATP-PRTs from higher plants and bacteria. It was demonstrated that the recombinant AtATP-PRTs were inhibited by L-His (50% inhibition of initial activity = 40-320 μM), suggesting that His biosynthesis was regulated in plants through feedback inhibition by L-His.
Journal Article
Intravenous immunoglobulin improves sepsis-induced coagulopathy: A retrospective, single-center observational study
by
Nakamura, Yoshihiko
,
Ohta, Daiki
,
Mizunuma, Mariko
in
Aged, 80 and over
,
Antithrombin III
,
Biomarkers - blood
2015
Inflammation and coagulation are closely interrelated processes in the pathogenesis of sepsis. This study aimed to determine whether intravenous immunoglobulin (IVIg) could improve the hyperinflammatory state and coagulation/fibrinolysis abnormalities in patients with sepsis.
Forty-one patients with sepsis were included. Nineteen patients were treated with IVIg (IVIg group; 5.0 g daily for 3 days within 2 days after hospitalization), and 22 patients were not (non-IVIg group). Inflammatory and coagulation/fibrinolysis molecular markers, Japanese Association for Acute Medicine disseminated intravascular coagulation score, and the Sequential Organ Failure Assessment score were evaluated in each group.
On admission, patients in the IVIg group had a significantly more severe condition. In the IVIg group, after treatment, C-reactive protein, procalcitonin, and interleukin-6 levels significantly decreased relative to values on admission. Also, compared with admission, the various coagulation/fibrinolysis molecular markers decreased after treatment. Moreover, the Japanese Association for Acute Medicine disseminated intravascular coagulation score and the Sequential Organ Failure Assessment score also significantly decreased after treatment. In contrast, in the non-IVIg group, only interleukin-6 level and thrombin-antithrombin complex levels significantly decreased. The 28-day mortality rate of the IVIg group was approximately one third of the value of the non-IVIg group (IVIg: 5.3% vs non-IVIg: 18.2%).
Intravenous immunoglobulin treatment significantly improved hemostatic abnormalities along with the hyperinflammatory state in patients with sepsis. Accordingly, IVIg treatment should be classified as an adjunctive therapy for patients complicated with sepsis-induced coagulopathy.
Journal Article
Benralizumab, an anti-interleukin-5 receptor α monoclonal antibody, as add-on treatment for patients with severe, uncontrolled, eosinophilic asthma (CALIMA): a randomised, double-blind, placebo-controlled phase 3 trial
by
Korn, Stephanie
,
Busse, William W
,
Aurivillius, Magnus
in
Administration, Inhalation
,
Adrenal Cortex Hormones - therapeutic use
,
Adult
2016
Benralizumab is a humanised, afucosylated, anti-interleukin-5 receptor α monoclonal antibody that induces direct, rapid, and nearly complete depletion of eosinophils. We aimed to assess the efficacy and safety of benralizumab as add-on therapy for patients with severe, uncontrolled asthma and elevated blood eosinophil counts.
In this randomised, double-blind, parallel-group, placebo-controlled, phase 3 study (CALIMA) undertaken at 303 sites in 11 countries, we enrolled patients aged 12–75 years with severe asthma uncontrolled by medium-dosage to high-dosage inhaled corticosteroids plus long-acting β₂-agonists (ICS plus LABA) and a history of two or more exacerbations in the previous year. Patients were randomly assigned (1:1:1) to receive 56 weeks of benralizumab 30 mg every 4 weeks (Q4W), benralizumab 30 mg every 8 weeks (Q8W; first three doses 4 weeks apart), or placebo (all subcutaneous injection). Patients were stratified (2:1) by baseline blood eosinophil counts 300 cells per μL or greater and less than 300 cells per μL, respectively. Patients and study centre staff were masked to treatment allocation. The primary endpoint was annual exacerbation rate ratio versus placebo for patients receiving high-dosage ICS plus LABA with baseline blood eosinophils 300 cells per μL or greater (intention-to-treat analysis). Key secondary endpoints were pre-bronchodilator forced expiratory volume in 1 s (FEV1) and total asthma symptom score. This study is registered with ClinicalTrials.gov, number NCT01914757.
Between Aug 21, 2013, and March 16, 2015, 2505 patients were enrolled, of whom 1306 patients were randomised; 425 patients were randomly assigned to and received benralizumab 30 mg Q4W, 441 to benralizumab 30 mg Q8W, and 440 to placebo. 728 patients were included in the primary analysis population. Benralizumab resulted in significantly lower annual exacerbation rates with the Q4W regimen (rate 0·60 [95% CI 0·48–0·74], rate ratio 0·64 [95% CI 0·49–0·85], p=0·0018, n=241) and Q8W regimen (rate 0·66 [95% CI 0·54–0·82], rate ratio 0·72 [95% CI 0·54–0·95], p=0·0188, n=239) compared with placebo (rate 0·93 [95% CI 0·77–1·12], n=248). Benralizumab also significantly improved pre-bronchodilator FEV1 (Q4W and Q8W) and total asthma symptom score (Q8W only) in these patients. The most common adverse events were nasopharyngitis (90 [21%] in the Q4W group, 79 [18%] in the Q8W group, and 92 [21%] in the placebo group) and worsening asthma (61 [14%] in the Q4W group, 47 [11%] in the Q8W group, and 68 [15%] in the group).
Benralizumab significantly reduced annual exacerbation rates and was generally well tolerated for patients with severe, uncontrolled asthma with blood eosinophils 300 cells per μL or greater. Our data further refine the patient population likely to receive the greatest benefit from benralizumab treatment.
AstraZeneca and Kyowa Hakko Kirin.
Journal Article
Examination of the diagnostic accuracy of sepsis using procalcitonin, presepsin and CD64 for patients with or without acute kidney injury
2015
Introduction At the moment, we have few reports about the diagnostic accuracy of procalcitonin (PCT), presepsin (P-SEP) and CD64 as a diagnostic marker of sepsis for patients with acute kidney injury (AKI). Blood samples were collected from 334 patients admitted to our ICU between April 2013 and March 2014.
Journal Article
Insect cell expression of recombinant imidazoleglycerolphosphate dehydratase of arabidopsis and wheat and inhibition by triazole herbicides
by
Tada, S. (Ciba-Geigy Japan Ltd., Takarazuka, Japan.)
,
Guyer, D
,
Nakayama, Y
in
ADN RECOMBINADO
,
ADN RECOMBINE
,
Amino Acid Sequence
1995
Imidazoleglycerolphosphate dehydratase (IGPD; EC 4.2.1.19), which is involved in the histidine biosynthetic pathway of Arabidopsis thaliana and wheat (Triticum aestivum), has been expressed in insect cells using the baculovirus expression vector system. N-terminal amino acid sequencing indicated that recombinant IGPDs (rlGPDs) were produced as mature forms via nonspecific proteolytic cleavages in the putative transit peptide region. The wheat rlGPD contained one Mn atom per subunit, and the Mn was involved in the assembly of the subunits to form active IGPDs. Protein-blotting analysis, using antibodies raised against the wheat rlGPD, indicated that IGPD was located in the chloroplasts of wheat. The rlGPDs of Arabidopsis and wheat, which were 86% identical in their primary structures deduced from the cDNAs, exhibited similar properties in terms of the molecular mass, pH optimum, and the Km for the substrate, imidazoleglycerolphosphase. However, the nonselective herbicides 3-amino-1,2,4-triazole and a newly synthesized triazole [(1R*, 3R*)-[3-hydroxy-3-(2H- [1,2,4]triazole-3-yl)-cyclohexyl]-phosphonic acid], inhibited Arabidopsis and wheat IGPDs in a mixed-type and a competitive manner respectively
Journal Article
Two Isoforms of NADPH:Cytochrome P450 Reductase in Arabidopsis thaliana: Gene Structure, Heterologous Expression in Insect Cells, and Differential Regulation
1998
We have investigated two NADPH-cytochrome (Cyt) P450 reductase isoforms encoded by separate genes (AR1 and AR2) in Arabidopsis thaliana. We isolated AR1 and AR2 cDNAs using a mung bean (Phaseolus aureus L.) NADPH-Cyt P450 reductase cDNA as a probe. The recombinant AR1 and AR2 proteins produced using a baculovirus expression system showed similar Km values for Cyt c and NADPH, respectively. In the reconstitution system with a recombinant cinnamate 4-hydroxylase (CYP73A5), the recombinant AR1 and AR2 proteins gave the same level of cinnamate 4-hydroxylase activity (about 70 nmol $\\text{min}^{-1}\\ \\text{nmol}^{-1}$ P450). The AR2 gene expression was transiently induced by 4- and 3-fold within 1 h of wounding and light treatments, respectively, and the induction time course preceded those of CYP73A5 and a phenylalanine ammonia-lyase (PAL1) gene. On the contrary, the AR1 expression level did not change during the treatments. Analysis of the AR1 and AR2 gene structure revealed that only the AR2 promoter contained three putative sequence motifs (boxes P, A, and L), which are involved in the coordinated expression of CYP73A5 and other phenylpropanoid pathway genes. These results suggest the possibility that AR2 transcription may be functionally linked to the induced levels of phenylpropanoid pathway enzymes.
Journal Article
Antibodies to the GABAB receptor in limbic encephalitis with seizures: case series and characterisation of the antigen
2010
Summary Background Some encephalitides or seizure disorders once thought idiopathic now seem to be immune mediated. We aimed to describe the clinical features of one such disorder and to identify the autoantigen involved. Methods 15 patients who were suspected to have paraneoplastic or immune-mediated limbic encephalitis were clinically assessed. Confocal microscopy, immunoprecipitation, and mass spectrometry were used to characterise the autoantigen. An assay of HEK293 cells transfected with rodent GABAB1 or GABAB2 receptor subunits was used as a serological test. 91 patients with encephalitis suspected to be paraneoplastic or immune mediated and 13 individuals with syndromes associated with antibodies to glutamic acid decarboxylase 65 were used as controls. Findings All patients presented with early or prominent seizures; other symptoms, MRI, and electroencephalography findings were consistent with predominant limbic dysfunction. All patients had antibodies (mainly IgG1) against a neuronal cell-surface antigen; in three patients antibodies were detected only in CSF. Immunoprecipitation and mass spectrometry showed that the antibodies recognise the B1 subunit of the GABAB receptor, an inhibitory receptor that has been associated with seizures and memory dysfunction when disrupted. Confocal microscopy showed colocalisation of the antibody with GABAB receptors. Seven of 15 patients had tumours, five of which were small-cell lung cancer, and seven patients had non-neuronal autoantibodies. Although nine of ten patients who received immunotherapy and cancer treatment (when a tumour was found) showed neurological improvement, none of the four patients who were not similarly treated improved (p=0·005). Low levels of GABAB1 receptor antibodies were identified in two of 104 controls (p<0·0001). Interpretation GABAB receptor autoimmune encephalitis is a potentially treatable disorder characterised by seizures and, in some patients, associated with small-cell lung cancer and with other autoantibodies. Funding National Institutes of Health.
Journal Article